Technical Field
The present disclosure is related to an illumination field, and more particular to a LED filament, a LED filament assembly and a LED Bulb.
Related Art
The LED has advantages of environmental protection, energy saving, high efficiency and long lifespan, and therefore it attracts widespread attention in recent years and gradually replaces the traditional lighting lamp. However, the luminescence of the LED has directivity and cannot may make an illumination with a wide angle range like the traditional lamp. Accordingly, how to design the LED Bulb with an extremely wide angle and light illuminated the entire circumference effect has become a research and development subject for the LED industry.
In the recent years, a LED light filament, which makes the LED light source lighting similar to traditional tungsten light bulb to achieve a full angle for illumination, is increasingly attracted by the industry. The manufacturing of the LED filament is that a plurality of LED chips are connected in series and fixed on a narrow and slightly long glass substrate, and a silicon gel doped with a phosphor wraps the whole glass substrate and the electrical connection is performed, thereby completing the LED filament. However, a thermal conductivity of the glass substrate is not good and is easily broken due to vibration, thereby disconnecting the series connection of the LED chips to incur the failure. Therefore, a metal substrate, which is not easily broken, is used to replace the glass substrate, but the light cannot penetrate the metal substrate and it has a defect of the light shielding. Thus the luminous efficiency of the LED filament is low. Accordingly, how to strengthen a robustness of the LED filament substrate and a thermal conducting property of the LED filament substrate as well as the luminous efficiency of the LED filament has become a research and development subject for the LED industry.